Steven Hobbs, a married Texas father of two charged with killing and assaulting prostitutes for the past decade, may be linked to several other unsolved murders in the area, investigators say.
"We're now going back to 15 years from today to check cold cases," Harris County sheriff's spokesman Alan Bernstein told ABCNews.com. "We're even talking to neighboring counties, which are much more rural, about their cases."
Hobbs, a 40-year-old, 6-foot-4 former security guard, has now been in jail for about two weeks, accused of murdering two women in Harris County and assaulting four others. But he might never have been apprehended if a Pasadena, Texas, motorcycle cop hadn't stopped to set up a routine traffic radar site.
On Sept. 22 the officer pulled over into a brushy area off Red Bluff Road to clock the speed of passing motorists. That's where he discovered what Bernstein described as "the key to everything" -- the badly decomposed body of Wanda Trombley, 57, who had been missing since July.
Her body was "maybe 30 feet from the entrance where Hobbs was [working as] a security guard," said Pasadena Assistant Police Chief Bud Corbett.
Detectives believe the murderer likely dumped Trombley's body in Pasadena because she had worked several miles away in northeast Houston. They began questioning prostitutes in that area.
One of them, a 43-year-old woman whose identity will remain anonymous, told investigators that in June a large white man with "reddish-blond hair and thick eyeglasses" had picked her up to go to a motel for sex, according to the Harris County District Attorney's Office.
But instead of driving to the motel, she said, he brought her to a desolate location on Wallisville Road in Houston, sexually assaulted her at gunpoint, handcuffed her arms and feet and beat her with what appeared to be a mop handle. At some point, she added, he put on a security uniform and spoke to someone on the phone who sounded like an employer.
Two other prostitutes also told detectives they were assaulted by a man fitting Hobbs' description wearing a security uniform.
When detectives showed the 43-year-old victim several mens' photos, she identified Hobbs' picture, saying she was "absolutely certain" that he was the man who had assaulted her.
Hobbs was charged with kidnapping and sexual assault, and also charged with the aggravated assault of 28-year-old prostitute Danielle Perfitt, which also occurred in June.
Investigators filed another charge for the 2010 aggravated assault of 33-year-old prostitute Sandra Gunter.
Meanwhile, detectives at the Harris County Sheriff's Department had been trying to solve other prostitute homicides in the county, and thought Trombley's case sounded similar.
They tested the DNA of the security guards who worked at the business near where Trombley was found.
"The swabs from Steven Hobbs matched DNA evidence at the scene of two murders that took place outside Pasadena but inside Harris County," said Bernstein.
This week, the Harris County District Attorney's office charged Hobbs with strangling prostitute and mother of five Patricia Pyatt, 38, in 2002, and sexually assaulting a woman, whose identity is being protected, that same year. The assault took place near the San Jacinto River, along the Beaumont Highway, not very far from where Pyatt's body was found.
He was also charged with murdering prostitute Sarah Sanford, 48, who was found nude and bound with handcuffs in a wooded area about five miles from Hobbs' home in 2010, according to police. She had been sexually assaulted and shot in the head. DNA from the handcuffs used to bind her, and from her mouth, matched that of Hobbs.
"He's not been cooperating with our detectives," said Bernstein.
Steven Hobbs Accused of Murder, Rape
Hobbs is, so far, only a person of interest in Trombley's death -- the murder that launched this entire investigation. Now, detectives say circumstantial evidence suggests he may have been involved in that and other cases.
"There's a lot of speculation," said Bernstein. "For instance, there was a woman found dead in same area as Patricia Pyatt in far northeast Harris County, but there's no evidence right now connecting a suspect to her."
Tracking down all of the alleged victims, however, will be tricky.
"There's no way to put a count on the number of unsolved murders of women who may have been involved in drugs or prostitution, or both," said Bernstein.
Prior to his recent arrest, Hobbs didn't have any documented run-ins with the law, except for "a minor traffic violation that landed him in this jail for a couple hours in 2000," Bernstein said.
Alan Isbell, one of two attorneys appointed by the court to defend Hobbs' murder charges, told ABCNews.com, "He comes from a very solid background and is known as a solid citizen -- a college graduate -- and we are contesting all charges."
The lawyers representing Hobbs on the assault charges did not immediately respond to an interview request.
Some of Hobbs' neighbors, who spoke to ABC News affiliate KTRK, said Hobbs came across as a loner.
Harry Naskrent told the station Hobbs was, "Very quiet, self-centered and off to himself."
ABCNews.com spoke with neighbor Cynthia Heath, 49, who lives down the street from Hobbs, his wife and teenage sons. She said she had never spoken to him, but "he looked like a very family-oriented person."
"His oldest son came by one day to visit one day by the driveway and looked like he was very well taken care of," she said. "Everybody's shocked. ... We're just shocked. It's a very peaceful, relaxing, lovely neighborhood."
Hobbs will appear in court again on Dec. 6, Isbell said, but the case probably won't go to trial for another year while detectives continue to examine old cases for any connections to Hobbs, who may now face the death penalty.
For now, detectives are asking other women who may have been assaulted to speak up.
"The more we publicize this, the greater the chance that someone who would have not have come forward because of their illegal activities will come forward now," said Bernstein.